Annual Changes in Seasonal River Water Temperatures in the Eastern and Western United States

Abstract

Changes in river water temperatures are anticipated to have direct effects on thermal habitat and fish population vital rates, and therefore, understanding temporal trends in water temperatures may be necessary for predicting changes in thermal habitat and how species might respond to such changes. However, many investigations into trends in water temperatures use regression methods that assume long-term monotonic changes in temperature, when in fact changes are likely to be nonmonotonic. Therefore, our objective was to highlight the need and provide an example of an analytical method to better quantify the short-term, nonmonotonic temporal changes in thermal habitat that are likely necessary to determine the effects of changing thermal conditions on fish populations and communities. To achieve this objective, this study uses Bayesian dynamic linear models (DLMs) to examine seasonal trends in river water temperatures from sites located in the eastern and western United States, regions that have dramatically different riverine habitats and fish communities. We estimated the annual rate of change in water temperature and found little evidence of seasonal changes in water temperatures in the eastern U.S. We found more evidence of warming for river sites located in the western U.S., particularly during the fall and winter seasons. Use of DLMs provided a more detailed view of temporal dynamics in river thermal habitat compared to more traditional methods by quantifying year-to-year changes and associated uncertainty, providing managers with the information needed to adapt decision making to short-term changes in habitat conditions that may be necessary for conserving aquatic resources in the face of a changing climate.

The Physico-Chemical Quality of Streams and Channels Draining into River Rwizi, South Western Uganda

“…Journal of Water Resource and Protection cordingly, most sites in the study did not demonstrate a consistent increase or decrease in water temperature during dry season months with annual probabilities of increase in water temperature varying over time as was similar to the findings of Wagner et al[32].Bus park and Kituntu streams both in downstream had the highest and the second highest temperature values possibly attributed to the increased human activities taking place within the two places. Kituntu had a bakery plant and the water from the plant is poured direct to the river which raised the temperature.Bus park is situated in a heavily populated slum area of Mbarara municipality characterized by different activities taking place which generate a lot of urban wastewater with high potential to increase the temperature of the stream.…”

Changes in the Water Temperature of Rivers Impacted by the Urban Heat Island: Case Study of Suceava City

“…An increase in water temperature of rivers all over the world due to global warming is depicted in numerous studies [1,2]. At the same time, the increasing urban population worldwide leads to a greater and more territorially focused impact of cities on the environment.…”

Thermal regime metrics and quantifying their uncertainty for North American streams

“…Like flow regimes, thermal regimes are of central importance in sustaining the ecological integrity of aquatic ecosystems. Water temperature has been described as the abiotic master factor for fishes (Brett, ; Hannah & Garner, ; Wagner, Whiƫer, DeWeber, & Paukert, ) and as an ecological resource (Magnuson, Crowder, & Medvick, ). Indeed, temperature influences the distribution and abundance of species, water quality, nutrient and ice dynamics, and the metabolic activity, growth, timing of migration, and spawning events (Caissie, ; Prowse, , ).…”